A car dealer from Brighton, Raby began racing in the early fifties in Formula 3 with specials which he christened 'Puddle Jumper', but he wasn't really competitive until he raced a Cooper in 1956. After two years with Cooper and Elva sports cars, Raby returned to single-seaters in 1959-60 with both a Cooper and a Hume-Climax, gaining success only in modest Formula Libre races.

In 1961-62 he raced mainly in Formula Junior, before buying the Gilby-BRM from Syd Greene to race in Formula 1 in 1963. Ian gained a third place at Vallelunga in the Rome GP, but precious little else, and in 1964-65 he relied on a Brabham BT3, still no more than making up the numbers.

With the new 3-litre formula in operation for 1966, Raby stepped down into F2 with a Brabham BT14-Cosworth. He scored a good fourth place at the Eifelrennen, before a crash at Brands Hatch curtailed his season. Despite his relatively old age, Ian undertook a full season of Formula 2 in 1967, gaining the occasional top-six finish, before a serious crash at Zandvoort left him hospitalised with multiple injuries to which, he succumbed some weeks later.